You can password protect Word Documents as well. So, keep that in mind (for privacy sake).
I had a job where there was a LOT of downtime and you were expected to keep yourself busy. We were allowed to surf the web or read a book, so writing wasn't a huge concern. That said, I too didn't want my writing seen by others, so I PW protected my documents. As for writing, I usually adjusted the size of the WORD screen so that it took up the bottom 1/3 of the screen and scaled the font to around 75% size.
Again, some jobs require that you "babysit" the phone or station during a GY shift and a lot managers will not care if you surf, read a book. Heck, I had one that let us play video games on our laptops that we brought in. While this might shock some people, it happens quite a bit. Saying, "Well you should be working not writing," may be true where you work, but not always true for other places. Besides, I could be misreading, but I think she asked "how" she can do it, not "should I do it." (Could be wrong in my interpretation.)
I actually quit a job because there was too much downtime and (believe it or not) after a while, surfing the web gets super old. I wasn't writing much at all then (a little). I wish I had, though. I ended up leaving because I needed more stimulation. The job was manning a help desk phone line. Sometimes, we would get 1-2 calls an hour. Sometimes 20. We couldn't get up and just go wandering around or look for something to organize or clean. We had to stick by the phones. (This was before cell phones were popular, so keep that in mind.)